The effect of cetirizine on plasma membrane fluidity and heterogeneity of human eosinophils, neutrophils, platelets and lymphocytes was investigated using a fluorescence technique. Membrane fluidity and heterogeneity were studied by measuring the steady-state fluorescence anisotropy and fluorescence decay of 1-(4- trimethylammonium-phenyl)-6-phenyl-1, 3, 5-hexatriene (TMA-DPH) incorporated in t...

The interaction of the divalent calcium ions with the zwitterionic lipid membranes was studied by measuring the lipid order parameter which is inversely proportional to the membrane fluidity. Small unilamellar lipid vesicles were prepared from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and then treated with different concentrations of divalent calcium ions. An increase in the order parame...

The effect of ticlopidine on platelet membrane fluidity was investigated using a spin label technique. Ticlopidine, when orally administered to rats, increased both the order parameter and the motion parameter, indicating a decrease in the membrane fluidity of platelets. On the other hand, the order parameter and the motion parameter decreased markedly when the platelets were aggregated by thro...

Porcine corpora lutea plasma membranes were treated with neutral lipids from hen egg yolk and a special mixture consisting of 70% neutral lipids, 20% phosphatidylcholine and 10% phosphatidylethanolamine. Membrane fluidity, as determined by fluorescence polarization of DPH, significantly increased already after 30 min of incubation of the membranes with lipids. The fluidization effect of neutral...

Since lysosomes are prone to osmotic lysis, we have examined the correlation between their physical state and sensitivity to osmotic challenge, using agents which modify membrane fluidity. The latency loss of beta-hexosaminidase after an incubation in hypotonic sucrose medium was followed under different conditions of membrane fluidity, recorded by steady-state fluorescence anisotropy of 1,6-di...

The interaction of Abeta with synaptosomal plasma membranes decreases membrane fluidity. Using model membrane/liposome systems the interaction of Abeta with specific lipids (e.g. phospholipids, gangliosides, cholesterol) has been defined. The formation of the beta-sheet structure of Abeta when undergoing peptide aggregation is important for Abeta's membrane perturbing properties. This effect ca...

The effects of the surfactants, alcohol ethoxylate, amine ethoxylate, amine oxide and SDS on cell membranes were investigated using the lipid soluble spin label 5-doxyl stearic acid (5-DS). Electron paramagnetic resonance (EPR) spectroscopy revealed that the action of the surfactants was to significantly increase membrane fluidity of Proteus mirabilis, Staphylococcus aureus and Saccharomyces ce...

Alterations in erythrocytes from Alzheimer disease patients were examined using EPR spectroscopy. Three spin-labeled fatty acids were applied to measure lipid membrane fluidity. A decrease of membrane fluidity was found in the deeper region of lipid bilayer of erythrocytes membrane, as indicated by 12-doxylstearic acid assay. The physical state of erythrocyte membrane proteins was estimated usi...